Dynamic Test for DC Training Emulation System with Back-to-back MMC

With the development of VSC-HVDC and engineering applications, establishing a modular multilevel converter (MMC) platform is extremely important for simulation research and training. In this study, a back-to-back MMC emulation system with a converter station level is developed. Dynamic tests are performed to verify the stability performance and the dynamic performance of the respective physical devices under asynchronous interconnection conditions. The results show that the system can perform automatic control for the sequence of blocking, uncontrolled charging, controlled charging, and unlocking operations. A remarkable power quality effect is obtained by using a controller for circulating current suppressing (CCS). Using a visual station operation interface, the dynamic index of the power step test is found to conform to the test standard, and the system exhibits stable operation.